[devb]

Why? Something to do with tidal influence on the core?

[raducu]

I'd also like to know. I supposed there must have been a lot of heat from the initial impact, tides must also happen inside the Earth, but I wonder how different the Earth would have looked like techtonically without the Moon?

No plate tectonics? So perhaps resurfacing event(s) like on Venus?

[jacquesm]

I suspect this is what the GGP was getting at:

https://www.discovermagazine.com/the-sciences/the-moon-our-s...